The scale and frequency of mass killings have been increasing, and this is likely to continue. One reason - but just one - is that weapons are always getting more lethal. One of the next technical innovations in small arms will be the use of artificial intelligence (AI) to improve the aiming of weapons. There is no reason for civilians to have this technology and we should ban it now. By lethality, I mean how many people you can kill in a short period. Lethality depends on many factors, including the weapon's rate of fire, but not just that. Depending on the circumstances, a shooter with a highly accurate bolt-action rifle may be able to...